CHC Healthcare

ToxocariasisSee also:ParasitesComplementary Healthcare ProductsToxocariasis is a very rare infection in humans caused by toxocara canis, otherwise known as roundworms. The parasites live in the digestive system of dogs and foxes. Eggs can be released in the faeces of infected animals and these contaminate soil. If someone accidentally ingests small particles of contaminated soil, they may develop toxocariasis.

The symptoms of toxocariasis in humans can vary depending on where in the body the infection occurs. In its mild form, it involves abdominal pain, a cough and headache. In other cases large numbers of parasites spread through different organs of the body such as lungs, liver and heart. Symptoms of this include fever, abdominal pain, and shortness of breath. The least common but potentially most serious type of toxocariasis is when the parasites move to the eyes. Symptoms include disturbed vision and irritation of the eyes. If left untreated, it can result in loss of vision in one eye.

With treatment, the outlook is very good and most people make a full recovery. Due to advances in treatment, the potential risk of blindness is now very rare.

Studies have revealed that only 5% of adult pet dogs, and 15% of stray or kennelled dogs excrete toxocara canis in their faeces.

The chances of humans developing toxocariasis are minimal. It is estimated that there are only about two new cases of infection per million of the population each year, according to the Pet Health Council. The National Health Service says that there are ten cases in Britain each year.

Children are most at risk, as they play in areas, such as grassland, where dog faeces are deposited. Children frequently put their hands in their mouths.

On the rare occasions where human disease occurs, it usually causes only mild symptoms. Only in exceptional cases does it cause damage to an eye.

Many surveys have been conducted throughout the world. Depending on the survey, between 0-27% of soil samples taken from public parks and private gardens contain toxocara canis eggs. Strangely, these eggs have also been found in soil samples from private gardens with no dogs.

Tests show that some 2% of adults in the UK have toxocara canis antibodies: they’ve been exposed to the eggs with no ill effects. The figure is not apparently higher for people who have regular contact with dogs, such as kennel workers.

In warm weather conditions, it takes between two and three weeks before any eggs within faeces become infective; longer in cold weather. However, if the faeces are left to weather down, the eggs can survive in the soil for up to three years.

So it makes sense to clear up after your dog. Apart from helping to minimise any risks to your friends, loved-ones and the wider community, you are also performing a public relations exercise for the dog population.